The present invention relates to a novel sample injection valve.
Separations of fluids are inherent in the liquid chromatographic process. Modern fluid or liquid chromatographic systems operate under very high pressures ie: up to 10,000 psi. Sample injection for the purpose of analysis and testing requires valving arrangements to permit loading and injection of the sample, as well as flushing of the sample reservoir.
Past systems of sample injection have involved the use of six port valves in conjunction with syringe injectors. The six port valve of the prior art usually included a stator and rotor acting in concert to connect or align ports thereon.
Existing six port valves encounter clogging problems due to the presence of particulate matter generated by the relative movement of the rotor and stator. It is known that the edges of the ports tend to scrape or spall valve facing materials and thus create particulate matter which aids in the clogging process hereinbefore described. Also, the mated plastic surfaces of the stator and rotor tend to deform under the extremely high fluid pressures encountered. Such deformation can lead to leakage and/or misdirection of carrier fluids. In addition, many prior valve designs suffer from having dead volume spaces which result in the obtaining of inaccurate results during the down stream analysis of the fluids.